GitLab

* Add SpatialEncoder and SpatialEncoder3d

* Optimize the code execution efficiency

* Fixed certain problems according to Dongyu's suggestions.

* Fix an error about probability of division by zero in PathEcoder; Change certain designs in SpatialEncoder

* Fix a typo

* polish the docstring

* fix doc

* lint
Co-authored-by: Ubuntu <ubuntu@ip-172-31-14-146.ap-northeast-1.compute.internal>
Co-authored-by: rudongyu <ru_dongyu@outlook.com>